1 //===- FuzzerExtraCounters.cpp - Extra coverage counters ------------------===//
2 //
3 //                     The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 // Extra coverage counters defined by user code.
10 //===----------------------------------------------------------------------===//
11 
12 #include "FuzzerDefs.h"
13 
14 #if LIBFUZZER_LINUX || LIBFUZZER_NETBSD
15 __attribute__((weak)) extern uint8_t __start___libfuzzer_extra_counters;
16 __attribute__((weak)) extern uint8_t __stop___libfuzzer_extra_counters;
17 
18 namespace fuzzer {
19 uint8_t *ExtraCountersBegin() { return &__start___libfuzzer_extra_counters; }
20 uint8_t *ExtraCountersEnd() { return &__stop___libfuzzer_extra_counters; }
21 ATTRIBUTE_NO_SANITIZE_ALL
22 void ClearExtraCounters() {  // hand-written memset, don't asan-ify.
23   uintptr_t *Beg = reinterpret_cast<uintptr_t*>(ExtraCountersBegin());
24   uintptr_t *End = reinterpret_cast<uintptr_t*>(ExtraCountersEnd());
25   for (; Beg < End; Beg++) {
26     *Beg = 0;
27     __asm__ __volatile__("" : : : "memory");
28   }
29 }
30 
31 }  // namespace fuzzer
32 
33 #else
34 // TODO: implement for other platforms.
35 namespace fuzzer {
36 uint8_t *ExtraCountersBegin() { return nullptr; }
37 uint8_t *ExtraCountersEnd() { return nullptr; }
38 void ClearExtraCounters() {}
39 }  // namespace fuzzer
40 
41 #endif
42